[Ben_Edict]

After many weeks of reading, and many more of saving, I finally arrived at a decision for my ultra-wide lens. Here are some of the reasons I chose the lens I did:

1) Could not get the lens I wanted: Wanted the Tokina 11-16mm f 2.8. I sent an e-mail to Tokina and asked if they might release this awesome lens in Pentax Mount--they did not even answer my e-mail. I have a vacation on the Applachian trail in early June, this ruled out Tamron's 10-24mm too.

2) What was said here was very influential: PentaxForums.com Third-Party Pentax Lens Review Database - 10-20mm F4-5.6 EX DC HSM (AF Lens)...

Also, the lens meters more accurately than anything I have used on my K20 for some reason. The AF is very quick and accurate. It comes with a hood & nice soft case. The lens exceeds my expectations.

Your first experiences very much reflect my own. I bought the 10-20 nearly 18 months ago, with very low expectations, basically just "to give it a try". But is far better and now is one of my favourite lenses. If you use it at f/8, sharpness and contrast leave not much to be desired. I just sometimes wish, it would be a f-stop faster...

Ben

[asdf]

What about the Pentax FA 20mm F2.8? The only thing it doesn't have on your wish list is the SDM/HSM. It is a screw drive auto focus, but it's quite quick. F2.8 is not F2.0 but it is around F2.0. Close focus, tack sharp even wide open, and that wonderful Pentax bokeh.

NaCl(one of my favorites)H2O

FA 20mm F2.8 sounds like a nice lens. I read about it before.

I'll keep dreaming about my fantasy ultrawide though.

[Jewelltrail]

Raybo: Nice lens JT!

The Sigma 10-20 was always on my wish list, please keep us (me) filled in on your results.

Ray

Thanks Ray, I have 5 weeks of vacation this year, some of which will be spent as far north as Mt. Katahdin (Maine), and as far south as Mount Mitchell (North Carolina) on the Appalachian trail and many surrounding areas. That will provide me with ample opportunity to produce some good stuff with this cool little lens, especially as I gain experience with it. I look forward to posting some good stuff in the coming months.

[Jewelltrail]

NaClH2O
Nice shots JT and congrats on your new acquisition. May you have many happy years with it.

NaCl(it's always cool to see somebody struggle over a decision and be happy with the outcome)H2O

Thank you, very much!

JT

[Jewelltrail]

Your first experiences very much reflect my own. I bought the 10-20 nearly 18 months ago, with very low expectations, basically just "to give it a try". But is far better and now is one of my favorite lenses. If you use it at f/8, sharpness and contrast leave not much to be desired. I just sometimes wish, it would be a f-stop faster...

Ben

Yes, agreed. I know there is a school of thought at the forum which believes f 2.8 does not belong on an ultra-wide lens. However, though my main purpose for my ultra-wide is outdoors, gathering landscapes, there are still times when I would love to have the extra F-stop myself. There are many ultra-wide opportunities inside beautiful & interesting buildings, for example churches, museums, aquariums and so on. Tri-pods are not always allowed, so F 2.8 has valid utility.

But I am talking a small % of my total shots might ever have need for this kind of speed. In some ways, as beautiful as this Sigma lens is, it almost feels gluttonous to be asking for more. But that Tokina 11-16mm f 2.8 sure does get me coveting at times. It is kind of silly, because the need is not wholly justified (I own Tamron 17-50 2.8) but it just seems nice to have the comfort factor of f 2.8 for any possible situation which might arise.

But I love this lens already & feel very fortunate to own it. Sigma has hit a Home run with this lens if you ask me.

[NaClH2O]

The 20mm is simply far from being a super-wide angle on a APS-C camera. The 10mm end of the Sigma (or any comparable other lens, even the 16mm end of the Pentax 16-50) is FAR wider.

Ben

Of course it is but the OP that I was quoting wrote: "between 10 and 20mm" the FA 20mm F2.8 meets those criteria.

NaCl(if they had said between 10 and 16mm I wouldn't have mentioned the FA 20mm)H2O

[EricT]

Yes, agreed. I know there is a school of thought at the forum which believes f 2.8 does not belong on an ultra-wide lens. However, though my main purpose for my ultra-wide is outdoors, gathering landscapes, there are still times when I would love to have the extra F-stop myself. There are many ultra-wide opportunities inside beautiful & interesting buildings, for example churches, museums, aquariums and so on. Tri-pods are not always allowed, so F 2.8 has valid utility.

But I am talking a small % of my total shots might ever have need for this kind of speed. In some ways, as beautiful as this Sigma lens is, it almost feels gluttonous to be asking for more. But that Tokina 11-16mm f 2.8 sure does get me coveting at times. It is kind of silly, because the need is not wholly justified (I own Tamron 17-50 2.8) but it just seems nice to have the comfort factor of f 2.8 for any possible situation which might arise.

But I love this lens already & feel very fortunate to own it. Sigma has hit a Home run with this lens if you ask me.

The rationale some people use is that the DOF is so thin at f/2.8. However, that's not true at 10mm. If you take a picture of something 5m away, you have a DOF from 3.7m to infinity!

[max11]

About the long debate between Pentax 12-24 and Sigma 10-20 f4/5,6 ...

1-The Pentax seems better, but having a 17-70, how much value I'd get from only 5 mm extra lenght? So maybe the 10-20 would be better.

2-About the Sigma: there are opposite opinion, also between good review sites: dpreview : Sigma 10-20mm F4-5.6 EX DC HSM Comparison to other wideangle zooms we've tested recently suggests the Sigma's class-leading days may be numbered. On APS-C, it simply can't match the biting central sharpness of the Tamron 10-24mm F3.5-4.5 Di-II in the 10-18mm range (for which, we suspect, users will mainly be buying this type of lens), and has more problematic distortion characteristics. However in a typical case of swings and roundabouts, the Sigma shows superior sharpness when shot wide open, and is better in the corners of the frame at all settings; it also has lower chromatic aberration, is better built and uses a superior focusing system."

while on photozone "The Sigma AF 10-20mm f/4-5.6 EX DC showed an pretty impressive performance with a few bugs. The resolution characteristic is generally very good to excellent except in the extreme corners at 10mm which are a bit soft at large aperture settings. A weak aspect of the Sigma is very high vignetting at large apertures - to be fair this is relatively normal regarding the extreme ultra-wide focal-length range. The CA characteristic (color shadows at the image borders) is generally pretty good except in the extreme corners at 10mm. The build quality of the lens is very high and leaves nothing to be desired. All in all a good alternative to the native Pentax lens"

3-waiting for the upcoming Sigma 10-20 f/3.5 HSM

[Jewelltrail]

Max 11: 1-The Pentax seems better, but having a 17-70, how much value I'd get from only 5 mm extra lenght? So maybe the 10-20 would be better.

I thought the very same thing; I own the Tamron 17-50 f 2.8.

[Ash]

Doesn't really matter too much - the 10-20's great anyway.
Different combos work for different people.
Even though I have the 16-50, the 12-24 I have does not become redundant.
The 12-24 peaks in performance at the short end, while the 16-50 peaks in the middle.
And my 10-17 is a different beast altogether.

[Jewelltrail]

Ash: Doesn't really matter too much - the 10-20's great anyway.

I agree, both the 12-24 & the 10-20 are great lenses. And you are right that different focal lengths have different strengths. I do not mind a little overlap in zoom ranges, but, in the end, the 10 & 11mm focal lengths were hard to say no to.

[max11]

I finally bought the 12-24.
5 extra mm are a lot, 2 extra much more. Anyway I went for Pentax due to the quality